1. Field of the Invention
The present invention is directed to the field of electronic storage of data and more particularly to that field applied to the area of measuring and storing data reflecting the distance traveled by a vehicle over its life.
2. Description of the Prior Art
Conventional odometers, as used in motor vehicles, have consistently employed mechanical accumulators such as are disclosed in U.S. Pat. Nos. 3,801,005 and 4,284,882. In each of those odometers, a gearing mechanism provides a scaled relationship between the linear distance traveled by a rotating vehicle wheel and the viewable number wheels. The odometer gear train is connected to drive a plurality of number wheels that are interrelated to count and permanently record the number of units (miles or kilometers) of distance traveled by the vehicle.
In more recent years, the trend has been to provide electronically activated digital readouts of critical information in a vehicle in the form of vacuum fluorescent or liquid crystal display systems. A digital speedometer is disclosed in U.S. Pat. No. 4,158,172 in which a pulse generator is employed to provide a known number of pulses per unit of distance traveled by the vehicle. Associated circuitry analyzes the rate at which the pulses are produced and provides appropriate signals to a vacuum flourescent display to provide a visible digital indication of the speed of the vehicle. Continuous sampling allows for the speedometer to update the display when a new speed value is detected and measured over a plurality of consecutive measurements.
In U.S. Pat. No. 4,317,106 an electronic device is indicated in which a similar speed sensing device is employed for measuring the wheel rotational speed of a vehicle and providing information which can be displayed in terms of distance that the vehicle has traveled since the system was reset. However, such a device is only intended as an auxiliary distance measuring device and would not be suitable for use as an odometer that permanently stores the accumulated distance the vehicle has traveled over its life, since there is no facility for permanently storing the distance values as they are accumulated.